How to select only those stations that have a quality flag of 'good' for the position and date/time

The quality flag for position is called “position_quality_flag” in the netCDF structure or "Q_POS" in the ASCII format file. It is a single character field and good positions are flagged with the character '1'. The variable “position_quality_flag” is used as a switch to control whether or not the data from the station being read are good or not. If position_quality_flag is anything other than 1, it is not good.

The quality flag for date and time is called " time_quality_flag" or "Q_Date_Time" in the netCDF structure and the ASCII format file, respectively. It is also a single character field and good observation dates and times are flagged with the character '1'.